I am going to be doing my first Belgian ale pretty soon (waiting for the temps to get a little warmer) and i want to avoid buying the 750ml bottles, what is the max volumes of co2 i should bottle condition it to without fear of my bottles blowing up?

i would love to get up to 4 but i have heard this is too high for regular bottles.

I've read of various people who have seen results from pressure testing of beer bottles. One said that the bottles begin to fail at 60 psi, another at 100 psi. It may depend on the manufacturer, since it seems obvious that some bottles are thicker than others. I've heard of some brewers weighing their bottles and taking the heaviest ones for high carbonation beer, assuming that these would be the thickest and sturdiest. I've also noticed that a lot of German beers seem to come in very thick bottles, probably because a lot of these need to hold up to being washed re-used by breweries in Germany.

Using a carbonation chart, I see that 50 psi (for a safety margin) would give 3.6 volumes at 75°F. So it seems that would be a guaranteed safe level for a stable bottle that is never raised above 75°F.

Above that would be a gamble, but even 4 volumes would be below 60 psi, if kept below 75°F. Even so, I would probably store these in a water proof container, like a plastic tote, that would contain beer and glass should the bottles explode. They should be safer once carbonated and refrigerated, where the pressure should be closer to 30 psi.

Most of my personal experience is toward the low end of the carbonation range, but I did have a Bitter that I thought was finished fermenting. The bottling sugar must have kicked it back into gear. By the time it was done, I was probably up around 4 volumes of CO2 (at a guess, it certainly wasn't the 1.75 I was aiming for). It ruined that beer by making it very carbonic, and every one was a gusher (which might happen to you, too) but my bottles held.

Good luck and be careful! I'd hate to hear that you had a bottle explode in your hand.